Clients with enhanced resiliency report a new meek version

psiphon/meekConn.go

@@ -50,7 +50,7 @@ import (
 // https://bitbucket.org/psiphon/psiphon-circumvention-system/src/default/go/meek-client/meek-client.go
 
 const (
-	MEEK_PROTOCOL_VERSION          = 2
+	MEEK_PROTOCOL_VERSION          = 3
 	MEEK_COOKIE_MAX_PADDING        = 32
 	MAX_SEND_PAYLOAD_LENGTH        = 65536
 	FULL_RECEIVE_BUFFER_LENGTH     = 4194304

psiphon/server/meek.go

@@ -57,13 +57,17 @@ const (
 	// report no version number and expect at most 64K response bodies.
 	MEEK_PROTOCOL_VERSION_1 = 1
 
-	// Protocol version 2 clients initiate a session by sending a encrypted and obfuscated meek
+	// Protocol version 2 clients initiate a session by sending an encrypted and obfuscated meek
 	// cookie with their initial HTTP request. Connection information is contained within the
 	// encrypted cookie payload. The server inspects the cookie and establishes a new session and
 	// returns a new random session ID back to client via Set-Cookie header. The client uses this
 	// session ID on all subsequent requests for the remainder of the session.
 	MEEK_PROTOCOL_VERSION_2 = 2
 
+	// Protocol version 3 clients include resiliency enhancements and will add a Range header
+	// when retrying a request for a partially downloaded response payload.
+	MEEK_PROTOCOL_VERSION_3 = 3
+
 	MEEK_MAX_REQUEST_PAYLOAD_LENGTH     = 65536
 	MEEK_TURN_AROUND_TIMEOUT            = 20 * time.Millisecond
 	MEEK_EXTENDED_TURN_AROUND_TIMEOUT   = 100 * time.Millisecond